1. Field of the Invention
The present invention relates, generally, to measurement apparatus and methods. Particularly, the invention relates to radial expansion force measurement apparatus and methods. Most particularly, the invention relates to an apparatus and method of measuring the radial expansion force which would be exerted by a balloon expandable or self expanding stent, stent graft, or similar medical device on the vasculature, which is also known as hoop force. The teachings of this invention are also applicable to other apparatus, methods and applications, including but not limited to catheters, balloons, tubes, conduits, filters, and the like whether in the medical field or other fields.
2. Background Information
Various medical procedures exist which involve inserting devices into the vasculature of a patient. These include endoscopy, biopsy, angiography, angioplasty, atherectomy, and the like. Percutaneous transluminal coronary angioplasty (PTCA) is a form of angioplasty which is performed to reduce or eliminate blockages in coronary arteries and restore or improve blood to flow heart tissue. Arteries are accessed by advancing a catheter through a percutaneous needle puncture made in the groin to the femoral artery, or arm to the brachial artery. A balloon disposed on the catheter is placed to opening a blockage caused by plaque in a coronary artery and inflated to open the blockage. A stent is a tubular structure, which may be drug coated, may be implanted at the blockage site via a catheter after angioplasty to keep the artery open and prevent regrowth of plaque or restenosis.
Hoop strength is a physical property that describes the ability of a tube to withstand internal pressure, bending and crushing forces. Hoop strength is an important characteristic of stents.
The state of the art includes various apparatus and methods of measuring force, in general. With respect to hoop force measurement, U.S. Pat. No. 6,568,235 to Kokish on May 27, 2003 entitled Assembly for Crimping an Intraluminal Device or Measuring the Radial Strength of the Intraluminal Device and Method of use discloses an assembly including a stationary disk, a drive disk, wedges uniformly spaced to provide substantially frictionless movement among the wedges, and linear sliders attached to a front face of the stationary disk.
This background technology is believed to have significant limitations and shortcomings. For this and other reasons, a need exists for the present invention.
All US patents and patent applications, and all other published documents mentioned anywhere in this application are incorporated by reference in their entirety.